How to spin or rotate same shape
Or.. using Dupliverts


Ensure the origin of your gondola is at the point you want to be attached to the wheel.
Create a 9-sided circle
Select the gondola, then the circle, and CtrlP parent the gondola to the circle
In the Circle's Object Properties > Duplication panel, check 'Verts' and uncheck 'Rotation'


 

As mentioned before, if you want to make the duplicates real, use CtrlShiftA.

This answer doesn't cover how to rig the wheel so when it's rotated, the gondolas swing independently, but I guess that's another question.

EDIT: having read @moonboots' answer... all you have to do to rig it is keep the hierarchy when you make the duplis real (you're given that option), and apply his 'Limit Rotation'  constraint.